1. Field of the Invention
This invention relates to a method of removing alkyltetralins coexisting in linear alkylbenzene (LAB) which is an intermediate raw material in making linear alkylbenzene sulfonate (LAS), a surfactant useful as a detergent for household and industrial use.
2. Description of the Prior Art
Presently, the surfactant LAS is used as a detergent for industrial use and/or household use on a large scale in the world including Japan, and manufactured by chlorinating n-paraffins of C.sub.10 -C.sub.14 separated from the kerosene fraction of petroleum to obtain the chlorinated n-paraffins. The chlorinated n-paraffins are reacted with benzene as an alkylating agent and sulfonated to obtain LAS.
Recently, it was found, during the alkylation reaction to produce the LAB, that some of the side chain alkyl groups are cyclized, as a side reaction, to produce alkyltetraline (AT) skeletons. The biodegradation rate of the alkyltetralins is slower than that of LAB's.
However, to date no practical technique for separating and removing the alkyltetralins contained in LAB has been developed.
As mentioned above, the biodegradation rate of the alkyltetralins is slow. On the other hand, since the production of LAS is so great in quantity, it is desirable, to minimize environmental problems, to minimize the presence of the alkyltetralins. However, no practical means capable of removing the alkyltetralins from LAS has been developed.